What is a mammal? And what is not a mammal? Mammals have skeletons as deer have, breathe air in lungs as whales do, and are born alive as are calves. What is not a mammal? A ladybug has no skeleton, ...

Planet Earth is in the Milky Way Galaxy, the cloudy band of light that stretches clear across the night sky. How many galaxies are there in the universe? For years astronomers thought that the Milky ...

A girl in a wheelchair looks down from her balcony and calls to passersby below: “Look up!”
Dog walkers, a bike rider, a kite flier, and dozens of commuters walk by without taking any notice. Then a ...